1. Field of the Invention
The present invention relates to a wireless power receiving device into which electricity is supplied wirelessly.
2. Description of the Related Art
Since a variety of electronic devices became widespread, many kinds of products have been shipped to market. In recent years, particularly, portable electronic devices for outdoor use have been remarkably widespread.
As an example of a portable electronic device for outdoor use, an RFID (radio frequency identification) tag (hereinafter referred to as an RF tag) has been actively researched and developed for practical use. The RF tag may be classified into two types: an active RF tag and a passive RF tag. On the other hand, other than the active RF tag and the passive RF tag, another type of an RF tag including a battery which is charged by using electromagnetic waves of a cell phone or the like in order to acquire electricity to drive the RF tag, has been developed. (Reference 1: Japanese Published Patent Application No. 2003-6592)
Note that an RF tag is also referred to as an IC (integrated circuit) tag, an IC chip, an RF chip, a wireless tag, and an electronic tag.
Note that charging a battery by using radio signals of electromagnetic waves is not only for an RF tag. Research and development on an electric energy feeder dedicated to charge a battery of a portable electronic device have also been actively conducted. (Reference 2: Japanese Published Patent Application No. 2003-299255)